1. Field
A linear compressor, a shell for a linear compressor, and a method for manufacturing a shell of a linear compressor are disclosed herein.
2. Background
Compressors are machines that receive power from a power generation device, such as an electric motor or turbine, to compress air, a refrigerant, or various working gases, thereby increasing in pressure. Compressors are being widely used in home appliances, such as refrigerators or air conditioners, or in industrial fields.
Compressors may be largely classified into reciprocating compressors, in which a compression space into and from which a working gas, such as a refrigerant, is suctioned and discharged, is defined between a piston and a cylinder to allow the piston to be linearly reciprocated in the cylinder, thereby compressing the working gas; rotary compressors, in which a compression space into and from which a working gas is suctioned or discharged, is defined between a roller that eccentrically rotates and a cylinder to allow the roller to eccentrically rotate along an inner wall of the cylinder, thereby compressing the working gas; and scroll compressors, in which a compression space into and from which a working gas is suctioned or discharged, is defined between an orbiting scroll and a fixed scroll to compress a refrigerant while the orbiting scroll rotates along the fixed scroll. In recent years, a linear compressor, which is directly connected to a drive motor and in which a piston is linearly reciprocated, to improve compression efficiency without mechanical losses due to movement conversion and having a simple structure, is being widely used. The linear compressor may suction in and compress a working gas, such as a refrigerant, while a piston is linearly reciprocated in a sealed shell by a linear motor and then discharge the refrigerant.
Noise may occur in the linear compressor. More particularly, vibration noise and airborne noise may occur due to a reciprocating motion of the piston used in the linear compressor, mechanical vibration and collision of other components, and refrigerant flow. The mechanical vibration may be transmitted into components forming a refrigeration cycle, such as an evaporator and a condenser, along a tube connected to the linear compressor, causing resonance, thereby making loud noise. The noise may cause inconvenience to a user of electronic equipment employing the linear compressor.
As the noise causes inconvenience to the user, it is estimated as a major factor for determining quality of a linear compressor. The linear compressors may vary in price according to a noise degree. For example, if noise of a linear compressor is reduced by about 1 dB, the linear compressor may rise in price by one dollar. In premium products, noise reduction in the linear compressor is a matter for a person in charge of R&D.
As drive frequency increases, the noise may increase. That is, the noise may increase in proportion to a square of velocity increment of a noise source. For example, if the drive frequency increases from about 60 Hz to about 120 Hz, the noise may increase by about 6 dB or more. The noise may increase over a whole noise frequency region.
For equipment, such as a refrigerator, in which the linear compressor is installed, there is a great need to increase a capacity of the refrigerator by reducing a volume of a machine room. Due to this trend, miniaturization of linear compressors is quickly progressing. As a result, the drive frequency of the linear compressor increases due to the miniaturization of the linear compressor. Thus, there is a requirement to reduce noise.
To reduce noise of the linear compressor according to the related art, a vibration absorber is used in a tube. However, even though the vibration absorber is applied to a high speed drive frequency of about 100 Hz or more, it may be difficult to sufficiently reduce the noise.